taking advantage of filles in folder other than destination folder - Tools

This is a discussion on taking advantage of filles in folder other than destination folder - Tools ; Dear Folks,
I have to backup pgsql database dump everynight on a routine. The database
dump actually contains sql(text) statements. The actual size of the database
dump is aroung 800 MB. Between two days backup, only few lines of statements
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taking advantage of filles in folder other than destination folder

Dear Folks,

I have to backup pgsql database dump everynight on a routine. The database
dump actually contains sql(text) statements. The actual size of the database
dump is aroung 800 MB. Between two days backup, only few lines of statements
are modified/added/deleted.

I dont want to do incremental backup. Instead, I want everyday's full dump
to be stored on to a folder named DD-MM-YY(ex: 01-05-08). Everyday there
will be a folder created with name DD-MM-YY and the dump will be stored
there.

Since the difference between the two day's backup are pretty minimal, I dont
want to resend the 800 MB files everyday.

Suppose,

1. I have taken yesterdays dump in a folder named 04-05-08 in database
server
2. I have rsynced the folder 04-05-08 to the backup server.
3. I have taken today's dump in folder named 05-05-08 in database server.
4. Now while doing rsync, I want rsync to compare the
05-05-08/dump file> with the <04-05-08/dump file> which already exists in
backup server. (then eventually, I want rsync to send only the differences
and store the output in folder 05-05-08).

Typicaly I want to take advantage of yesterday's file which already present
in a different folder.

Can anyone suggest a working method to implement this ? (I tried --copy-dest
/ --compare-dest .. but couldnt get it to work)